Field of Invention
This invention relates generally to glare screens/shields which diminish glare reflected from rear view mirrors, and more specifically to glare screens/shields which diminish glare from exterior rear view mirrors located on the driver's side of automobiles.
Discussion of Problem that Invention Addresses
Glare from the head lights of trailing vehicles, reflected from an automobile's rear view mirrors, is not only a common annoyance to drivers, but also a potential hazard. Safety becomes an important issue when the eye is subjected to glare during nighttime driving. In fact, research recently completed by Michigan's Ferris State University College of Optometry shows that stopping distances may be increased by as much as 100 feet at 60 m.p.h. when a driver is subjected to headlight glare at night. Glare causes an "after image" on the eye's retina, impeding the driver's ability to see and react to objects in the vehicle's path. The "after image" remains on the retina for several minutes, increasing the driver's reaction time, and creating an unsafe driving environment.
Studies also show that headlight glare at night increases driver fatigue. This is an important finding since the increasing traffic on our roadways, due to increased population, will naturally increase the incidence of head light glare. It is entirely possible that along with fatigue, headlight glare may also cause a driver to become irritated and, in isolated cases, could even trigger a road-rage incident. Now, while human psychology is not within the scope of the present invention, it is within the context of its intended function. That function is simply to make night driving a safer experience and, perhaps, a little more enjoyable.
Discussion of Prior Art
In order to minimize reflected glare, interior rear view mirrors are commonly equipped with some mechanism to reduce the glare associated with headlights from a trailing vehicle. This usually consists of a toggle switch that shifts a prismatic mirror between the two positions of a regular reflection and a dimmed reflection to prevent glare. One interior rear view mirror which has a nonglare option is described in U.S. Pat. No. 4,527,860 issued Jul. 9, 1985 to James A. Roof. A mirror such as this effectively solves the problem of headlight glare reflected from the interior rear view mirror.
Unfortunately, this type of prismatic mirror, is not effective for use as an exterior rear view mirror. The draw back of this design is that a prismatic mirror, mounted on the exterior of an automobile, would tend to produce ghost images which are visible to the driver in the face of that mirror.
There have been numerous attempts to prevent blinding glare which is reflected by exterior rear view mirrors. One example appeared in the USA Today newspaper on Wednesday, Nov. 8, 1989. It was an advertisement on page 8D that read "You'll never be blinded from the back again!", relating to a device called GLAREBUSTERS, which is similar to the present invention in that its intended function is to decrease headlight glare of vehicles approaching from behind. GLAREBUSTERS night driving shields comprise a two unit set, each part of which comprises a tinted plate of DuPont LUCITE and a plurality of suction cups to removably attach the plate to a car window. This same design is described in U.S. Pat. No. 4,943,103 issued Jul. 24, 1990 to John B. Rosen. Although this type of shield may serve to reduce headlight glare, one problem is that of it not being large enough to block the glare if the driver shifts positions relative to the GLAREBUSTERS. The main concern however is that this device, once mounted, gives only a nonglare, "dimmed" view of the moving vehicles behind. So, if the driver of a vehicle from behind is, for the moment, using low-beam headlights, and those headlights are properly adjusted, then the image of that vehicle's lights may be unnecessarily dark in the exterior rear view mirror of the driver of a leading vehicle. This situation could cause a miscalculation in distance or, even worse, it could possibly obscure the drivers vision to the point of him/her not being aware of an approaching vehicle. Simply stated, it is extremely important that any device which is used to prevent headlight glare reflected from the rear view mirrors of a motor vehicle, should be switchable between a normal reflection and a nonglare reflection. In addition, such a device should be easily switchable with one quick motion that does not divert a drivers attention from the road.
Another anti-glare shield similar to the present invention is described in U.S. Pat. No. 4,560,251 issued Dec. 24, 1985 to Waldemar Murjahn. This patent discloses an antiglare shield for exterior rear view mirrors which comprises an antiglare sheet, a stop, and a section which fits in an interior section of a vehicle's window shaft. This antiglare shield covers a larger area than does the GLAREBUSTERS, and has a part of the shield wedged into the window shaft. This design is very similar to U.S. Pat. No. 4,921,296 issued May 1, 1990 to Carl A. Gruber. Neither of these glare shields are integral to the car. More importantly, neither are switchable from nonglare to the regular reflected image which is normally seen in the exterior rear view mirror. As stated above, this is a definite disadvantage of these designs.
French patent 2,500,795 issued to Jean-Claude Tamagna and U.S. Pat. No. 4,865,421 issued Sep. 12, 1989 to Chih-Hsiung Lu and Jill Hui-Ju Lu are two patents which disclose very similar antiglare shield designs. Both designs comprise a plate of antiglare material which is installed and stored in a car door's window shaft, on the interior side of the window, in such a way that it may be rotated within a driver's line-of-sight of his/her exterior rear view mirror. This device is pivoted at a front edge and can be rotated into and out of position, when required, as easily as one would toggle the interior rear view mirror into and out of its nonglare mode. One problem with this device, however, is that it needs a large space in the interior of the window shaft to be stored properly. This means that car doors would have to be designed and built to accommodate this device. Unfortunately, car makers are unlikely to go to the extra trouble and expense, which regrettably renders this design impractical.
U.S. Pat. No. 5,089,912 issued Feb. 18, 1992 to Gerald L. Simin describes a retractable antiglare shield for an exterior rear view mirror that is mounted in a vehicle door and includes a flexible shield which can be stored in the door when not in use. This shield is supported on a roller mechanism and has its upper end formed with a support member which is insertable between the window and the door frame for maintaining the shield in the operative raised position. This particular design would have to be built into the door by auto makers before becoming available to the general public. The roller mechanism would seem to be prone to malfunction after initial use, as it resembles an up-side-down window blind commonly seen in homes, and would most probably be subject to the same misalignment problems. In addition, moving this shield between its operative and its retracted positions, aside from being somewhat clumsy, would require too much manual manipulation to make it a safe operation while driving. Once again, here is a device that can not be switched back and forth easily to provide both a regular view and a nonglare view of the image seen in an automobile's exterior rear view mirror.
Additional Background--Related Prior Art
A related device to that of the present invention is disclosed in U.S. Pat. No. 5,252,997 issued Oct. 12, 1993 to Charles R. Christenbery and describes a device that relates broadly to vision wear such as eyeglasses or sunglasses, which is more particularly a visual aid to be worn during nighttime driving. This visual aid has a glare reduction arrangement on both lens of the "eyeglasses". Though this type of device may well reduce glare to the night-driver, it may also impede the drivers view or cause an annoying eye strain that could lead to driver fatigue.
Another related device is described in U.S. Pat. No. 5,179,471 issued Jan. 12, 1993 to Gregory Caskey, Rodney Arendsen, and Niall Lynam. In essence, this device is a spectrally selective, glare-reducing mirror for vehicles. This is a high-tech answer to nonglare mirrors for both interior and exterior rear view mirrors in automobiles. Similar mirror called Electrochromic rearview mirrors are associated with the Gentex corporation. These automatic nonglare rear view mirrors would seem to be a superior way to solve glare problems for drivers. The drawback, however is that not only are they expensive, but also available on only a very few high-end vehicles. These mirrors can not be purchased and installed as after market items in a driver's present vehicle. And although these mirrors may become more readily available in a wider variety of new automobiles in the future, it will be several years distant. Even then, it would take many more years for the older model vehicles, still on the road, to be phased-out and replaced by the newer vehicles, equipped with this particular technology. This phase-in would happen only gradually. In short, advanced as it is, this technology will be a long time coming for the average consumer.
Other vehicles window glare shields and screens are disclosed by U.S. Pat. Nos. 1,180,589 Kubat; 1,454,498 Whall et al.; 1,920,185 Carr, Jr.; 1,953,877 Chase; 2,261,301 Smith; 2,594,813 Seibert; 2,665,166 Roark; 3,025,098 Andrews; 3,410,602 Schuler; 3,412,506 Masayoshi Shiota; 3,415,569 Leevo; 3,454,301 Lehmann; 3,518,427 Cotterill; 3,948,554 Barbee; 4,023,856 DeRees; and 4,130,317 Lai, 2,962,721 Epsy, 3,022,109 Hauskama, 4,261,649 Richard, 5,022,701 Thompson, II.